CRISPR-Cas9 z-bo 2020-11-16 330

　　It is estimated that one in ten people over the age of 65 suffer from this symptom, and this disease will increase with the increase of aging. AMD is very common among white people, and it causes visual distortions and blind spots. Scientists from the Genomic Engineering Center of the Korea Institute of Basic Science (IBS) reported that they used CRISPR-Cas9 technology to perform "gene surgery" on a certain layer of tissue that supports the retina in living mice.

　　The most common retinopathy that causes blindness includes: retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration. In these diseases, the secretion of vascular endothelial growth factor (VEGF) reaches abnormally high levels. For AMD, VEGF can cause new blood vessels to form in the eye, but it can also cause blood and body fluids to enter the eye and damage the central area of the retina, which is the macula.

　　"Injection of anti-VEGF drugs is the most common method to treat AMD, but at least 7 injections a year, because the diseased retinal pigment epithelial cells will continue to secrete VEGF. IBS scientists believe that CRISPR-Cas9 technology can improve this situation. KIM Jin-Soo, head of the Genome Engineering Center, explained: “Injection can only treat the symptoms but not the root cause. By editing the VEGF gene, we can cure this disease for a long time.”

　　CRISPR-Cas9 can precisely cut and repair specific locations in genes. The CRISPR-Cas9 system works by cutting DNA at the target location, in this case, cutting the VEGF gene. Two years ago, IBS scientists demonstrated that a pre-assembled CRISPR-Cas9, or Cas9 ribonucleoprotein (RNP), can be introduced into cells and stem cells to modify target genes. This pre-assembled molecule can take effect quickly and can be degraded before it can build an immune response. Although this method has advantages and has been successful, there are still difficulties in introducing pre-assembled molecules, which limits its application in therapy.

　　In the study, the research team successfully injected CRISPR-Cas9 into the eyes of mice suffering from wet age-related macular degeneration and modified the VEGF gene. They initially found that the injection method was more effective than plasmid introduction. Secondly, this compound will degrade and disappear within 72 hours. Scientists examined the mouse genome and found that the CRISPR-Cas9 molecule only modified the VEGF gene and had no effect on other genes. They monitored the progress of eye diseases by observing choroidal neovascularization (CNV). CNV is a newly formed blood vessel between the retina and sclera. It is a common problem in wet macular degeneration. The researchers found that the CNV area was reduced by 58%. In addition, the side effects of pyramidal dysfunction lasted only 3 days and did not reappear one week after treatment.

　　Kim Jin-Soo said: "Our method suppresses CNV by turning off the VEGF gene. We expect that in the future, surgeons can use this method to treat patients."

　　CRISPR-Cas9 used to be used to repair genetic mutations that cause genetic diseases and cancer. This study proposes a new method for the treatment of non-genetic degenerative diseases. Professor KIM Jeong Hun of Seoul National University pointed out: "We have confirmed that this method is effective in animal models, and now we hope to conduct preclinical trials."